Incremental drive assembly



United States Patent I [72] Dem, mom, 3,132,197. 5/1965 Turner et at....,. 2's4/t28x wu-mmkr, Colorado 3,136,48l 6/ l964 Handley 234/l 28X [2'] APPL No. 7 3 13 3,l 8|,759 5/1965 Maples 226/t57X [22] Filed s 27 19 3,l9.8 ,024 3/1965, Hanson 234/128X pilltfmed Nay-1711970 Primary Examiner-William S. Lawson [73] Asstgnee Uptlme C 'PQ Y Attomey-Sheridan and Ross Englewood, Colorado 'a corporation of Colorado 54 INCREMENTAL DRIVE-ASSEMBLY l l ABSTRACT: Incremental drive to move record card step by 7 Claims, 5 Drawing Figs. v

step through punching machine and avoid narrow web m 234/128 between first and second columns includes eccentric shaft and two spaced camshafts. Cam follower arms rock angularly on l 5 m 3/07 cams and carry pawls which reciprocate radially in response to [50] Field olSearch 234/l28, eccenmq and have dogs out ends to akemalely engage 129; 226/120, 146. I48. I57; 271/5 eeth in ratchet wheel for stepped rotation as cams rock. Pawls spring biased outwardly free of ratchet wheel between cards. [56] References cued At signal, pawl actuators resiliently force pawls against eccen- UNITED STATES PATENTS tric to follow it and drive ratchet wheel. Electrically controlled 3,0l7,077 ll l962 Herpin 234/128 latch means to hold pawl actuators in retracted position.

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a 2 f so i l a r32 40 a I54 6e t J l v z I72 Patented Nov. 17, 1970 Sheet 1 of 5 INVENTOR. DENNIS R. OLMSTED AT TORNEYS Patented Nov. 17, 1970 Sheet ATTORNEYS Patented Nov. 17, 1970 Sheet INVENTOR. DENNIS R. OLMSTED ATTORNEYS 'mcREMENfAL naive ASSEMBLY sAcxoRouND or THE lNVENTlON This invention lies in the general field ofthe incremental, or

step by step,-.drive mechanism. lt is directed to such mechanisms which are used to move business record cards through punching machines where they are punched to correspond to the-pattern in a master card. lt is particularly directed to adrive assembly which will insure that the card is very accurately located for the first punch column with respect to succeeding columnsto prevent formation of a web between the first and second column which is narrower than the design standard.

Record cards are presently moved through a punching machine. orpunch unit, in step by step progress which is synchronized with the operation of punching devicesso that the card is momentarily stationary aseach column is located under the punch. If any holes are indicated for the particular column, cam means drive the punches through the card and retract them during this momentary halLThe card is driven at up by manufacturingtolerances. The machine is initially adjusted so that both dogs are centered in their respective recesses withthe latches released and both arms tracking the cams. However, when the arms are latched and both dogs eng'aged, this adjustment is disturbed and a torque is induced in the ratchet wheel. When the release signal is given and the first pawl isreleased from its recess, the ratchet wheel accelerates-forward to the'limitof the pawl clearance and other I tolerance buildup. The hole in the first column is punched when in this forward condition, and then the ratchet wheel rocks back to its normal position. The second pawl now moves itsmargins'by a pair of feed wheels which have high friction edges to prevent slippage. These wheels must stop and start for each column and move the card an exact incremental distance each time. The standard cardnormally has 51 or 80 ,columns .and passes through the punch'unit in one-half second. Consequently the'drive means for the feedwheels must be very accurate in design and manufacture since faulty location of columnswill cause errors in reading. v

One form of drive means which has been proposed and tried includes a ratchet wheel connected directly to the'feed'wheels and is preferably fixed on the same drive shaft for rotation in unison. The rim of the ratchet'wheel is provided with a series of evenly spaced outwardly opening recesses around its periphery so that it resembles a spur gear. The mechanism to cause this ratchet wheel to rotate step by step includes a central shaft coaxial with the ratchet wheel. The latter may be forindependent rotation. t c n v A pair of lateral shafts are mounted parallel to the'central shaft and at opposite sides thereof and are connected by a gear train which i'n turn'is driven'by adriv'ege'arconnected to the other mechanism of the punchunit to. causeall shafts to rotate at the desired speeds and in the desired phase relations. The central shaft is provided with an eccentric adjacent tothe ratchet wheel and pivotally supportsa pair of'elongate ca'm follower arms extending radially in opposite directions from the axis of the shaft for rocking motion. 1

Each lateral shaft is provided wit'h a cam in the plane of its respective cam follower arm to rock the arm through an angle of a few degre es, an d a spring engages the opposite side of each arm to yieldingly urge the arm into tracking engagement with its cam. An elongate pawl isslidably mounted on each arm in longitudinal alignm'ent'therewith and has a foot at its inner end to track the eccentric and alug or dog at its outer end extending parallel to the axes of the shafts'and adapted to engage in one of the recesses in'the rimcf the ratchet wheel. A bias spring connected to the pawl and the armyieldingly urges the pawl radiallyinward to contact the eccentric. v

With this arrangement, thelpawl dogs alternately engage in the recess and thereis a small amount of overlap because of the singleeccentricso that at times b oth pawl dogs engage recesses tov a greateror less extent. 'I'heangular phasing of the eccentric and the cams is chosensothateach pawl dog enters its adjacent recess at its respective cam follower arm ridges its cam from the high dwell to the low dwell under the force of its spring and drives the ratchet wheelthrough the desired angular increment-The oppositedog leaves its recess and returns in the opposite angular direction outside the periphery of the ratchet-wheel.

When a card is placed in position ready for the first punch,

. ideally the feedwheels should bestationary. Therefore, it is necessary to prevent any, rotation of theratchet wheel. This is attempted by providing a latch for each cam follower arm the wheel forward a'normal step to the second column position but'the'distance is effectively foreshortened because of the error in the position of the first column.

' One disadvantage of the situation described above is that photoelectric devices for detecting misregistration of holes must be provided'with more tolerance than desired because of the known error in the first column .and the consequent narrow web. Another disadvantage is that the eccentric loading andsudd'enstress changes frequently cause broken ratchet mounted on the end of the central shaft by means ofa bearing 7 time" of the machine.

SUMMARY OF THE INVENTION The device of the present invention overcomes the difficulties mentioned above by eliminating the latches for the cam the'elements of theold device in the same form except the latches for the cam follower arms. However, the pawl springs are so connected as to bias the pawls radially outwardly infare freeto track the cams at all times. Therefore they rock whenever the apparatus is in motion.

A bracket. is 'mounted'adjacent to each arm and a pawl actuator is pivotally mounted on each bracket. The actuator is in strong enough to override the spring bias of the pawl and yieldingly urge -it-into tracking engagement with the eccentric .so that the pawl'dog will-periodically engage a recess of the ratchet wheel at the appropriate time to move it angularly forward as the arm rocks.

' When it is desired to prevent rotation of the ratchet wheel, the actuator must-be locked out of action so that the pawl dogs will clear the rim'of the ratchet wheel as they rock back and forth. The actuator is pivoted intermediate its ends so that its second end swings in an are opposite to the first end. A latch lever is pivotally mounted on the bracket intermediate its ends, and a first end is adapted to swing into the path of movement of the second end of the actuator when the related pawl reaches its outermost position. This blocks return movement of the actuator, and the outwardly biased pawl will not track the eccentric- The'first end of the latch lever is urged to its latching position by a spring, and a solenoid on the bracket is adapted to attract the second end to swing the lever out of latching position. Thus, to set the ratchet wheel in motion, the actuators are released, causing the pawl dogs to engage the ratchet wheel in normal fashion with only the normal engagement force. The wheel is not rocked out of its normal position and the card is properly located for punching of the first column.

BRIEF DESCRIPTION OF THE DRAWINGS Various other advantages and features of novelty will become apparent as the description proceeds in conjunction with the accompanying drawings, in which:

FIG. 1 is a side elevational view, partly in section, illustrating a punch unit to which the device of the invention is attached;

FIG. 2 is an exploded view in perspective showing details of the old and new apparatus;

FIG. 3 is a plan view, partly in section of the ratchet wheel and some associated parts;

FIG. 4 is a diagrammatic elevational view showing details of the old and new apparatus; and

FIG. 5 is a diagrammatic elevational view showing the principal details of the new apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENT One type of punch unit with which the apparatus of the invention is intended to be used is illustrated in FIG. 1, in which a main support carries a base plate 12 and a punch die 14 vertically spaced just sufficiently to slidably receive a record card entering through guide slot 16. The card is first located at the proper starting point and then fed step by step across the punch die. At each step, if so indicated by a master card, one or more punches 18 will be driven through the card into die 14 by a revolving punch cam 20 and immediately retracted by restore cam 22 acting through lever 24 on the under side of head 26 ofthe punch.

As is well known, the punch cam rotates continually in roper phase with other parts of the apparatus and drives spring loaded blade 28 down toward the head 26 of the punch. The blade traverses only a short portion of the gap between it and the punch. If one or more holes are indicated for the particular column, one or more interposer blocks 30 carried by arms 32 and actuated by interposer assembly 34 will be shifted into vertical alignment between blade 28 and their respective punch heads 26. Since they fill the gap, the corresponding punches 18 will be driven down through the card to produce the holes called for. The punches are then raised by levers 24 and the card moves to the next column. The necessary step by step movement of the card is produced by punch feed wheels 36 which engage the margins of the underside of the card with their abrasive rims. The wheels are fixedly mounted on drive shaft 38 for rotation therewith and the shaft in turn is connected to the incremental drive assembly.

The other end of drive shaft 38 is fixedly connected to ratchet wheel 40, Fig. 2, having a rim 42 provided with a series of outwardly opening recesses 44 evenly spaced around its periphery to be engaged by driving means to be described in a step by step or incremental angularmovement, rotating wheels 36 in a corresponding manner. The driving means in cludes three parallel shafts consisting of central shaft 46, coaxial with drive shaft 38, and two lateral shafts 48 and 50. Gear 52, keyed on shaft 46, meshes with gears 54, 56 keyed on shafts 48 and 50 respectively, and a drive gear 58 connected to the main driving means meshes with gear 54 to cause all of the shafts to rotate simultaneously. The pitch diameter of gear 52 is one half that of gears 54 and 56 so it rotates at twice their speed, and it rotates in the opposite direction.

Oppositely radially extending elongate cam follower arms 60 and 62 are mounted on shaft 46 for free rocking independent of the rotation of shaft 46, and each is provided with a cam engaging roller 64 and 66. These rollers are adapted to engage two-lobe earns 68 and 70 fixed on the ends of shafts 48 and 50 for rotation therewith in the manner illustrated in FIG. 4, the cams lying in the same transverse plane with the arms. Springs 72 and 74 mounted on brackets 76 and 78 are biased to force the arms against the cams when the arms are free of the latches, described later, so that the arms will track the cams and rock about an arc of a few degrees.

The free end of shaft 46 carries a bearing 80 to mount ratchet wheel 40 coaxially for independent rotation and also carries an eccentric 82 fixed to the shaft adjacent to the bearing, as seen in FIGS. 2 and 3. Elongate pawls 84 and 86 are aligned with arms 60 and 62 and slidably mounted on the sides nearest to the ratchet wheel for radial movement in and out, tracking the eccentric as it rotates. For this purpose, the inner end of each pawl is provide'd with a foot to ride on the cam, and a spring 88 connected between each arm and its respective pawl biases the latter toward the eccentric. The outer end of each pawl is provided with a lug or dog 90, 92 extending parallel to the axes of the shaft into the plane of ratchet wheel Assuming that both cam follower arms are free to track the cams and considering FIG. 3 and 4, it will be seen that rotation of the eccentric causes thepawls to move radially in and out and they are of such length that dogs 90, 92 move into adjacent recesses 44 of the ratchet wheel and outward beyond its periphery. Each dog begins entering before the other one is entirely clear so there are times when both dogs engage the recesses to a greater or lesser extent. The angular phasing of the cams and eccentric is so chosen that each dog begins entering an adjacent recess in the ratchet wheel as its arm leaves the high dwell of a cam lobe and its respective spring moves the arm angularly to follow the cam. During this movement, the ratchet wheel is rotated angularly to the desired extent. During the same period, the opposite dog is leaving its recess and its arm is moving angularly in the opposite direction against the bias ofits spring. Thus the alternating action of the arms and pawls produces incremental rotation of the ratchet wheel and the punch feed wheels to produce step by step movement of the card through the punch unit.

It is necessary to stop the incremental feed whenever a new card reaches the punch unit but it is undesirable to stop all of the rotating machinery. This is taken care of by providing latch means to-restrain rocking movement of the cam follower arms. As seen in FIG. 4, the outer end of each arm is provided with a latch pin 94, 96. A bracket 98, is mounted adjacent to the end of each arm and pivotally carries a latch arm 102, 104 provided at its free end with a latch hook 106, 108 to engage its respective latch pin. The latch arms are urged toward the arms by springs 110, 112 and may be retracted by solenoids 114, 116.

When it is desired to stop the incremental feed, arms 102 and 104 are allowed to extend so that their hooks will catch the latch pins as the arms ride the high dwells of the cams. When the feed is to start again appropriate signals are delivered to thesolenoids. For this purpose, a logic center 118 is provided. Sensing means 120 senses the angular rotational position of magnetic disk 122, mounted on shaft 48, and sends signals to the logic center which in turn. sends signals to the solenoids 114 and 116 at the proper moments to cause successive release of the two cam follower arms.

It is at this point that the difficulty arises which was described above. Both pawl dogs are engaged in recesses in ratchet wheel 40 and arm 62 is not tracking its cam 70. The strain in the ratchet wheel is suddenly relieved as dog 92 of pawl 86 leaves its recess. The wheeljumps ahead, overfeeding the card, and the first column hole is punched too close to the second column position, after which the ratchet wheel rocks back to normal position, and all succeeding column punches are properly spaced.

All of the incremental drive apparatus is mounted on a support 124 which is attached to the side ofthe punch unit.

In the modified apparatus shown in FIG. 5, shafts 46, 48, and 50 are driven in the same way as before and carry the eccentric 82 and earns 68 and 70. Cam follower arms 60, 62 are mounted to rock on shaft 46. Elongate pawls 126 and 128 are mounted for sliding movement on arms 60 and 62, and are provided with feet 130, 132 to ride the eccentric and with heads 134, 136 at their outer ends carrying dogs 138, 140 to engage recesses 44 in the ratchet wheel. However, springs 142 are secured to the arms at 144 and to the pawls at 146 to bias the pawls outwardly rather than inwardly so that they will not track the eccentric in the absence of some extraneous force.

Brackets 148, 150 are mounted adjacent to the ends of the arms 60, 62 and on each bracket a pawl actuator 152, 154 is pivotally mounted at 156, 158 intermediate its ends 160, 162 and 164, 166. Springs 168 urge actuator ends 160, 164 against the pawl heads 134, 136 with enough force to override springs 142 and cause the pawls to track the eccentric so that the dogs 138,140 will successively engage recesses in the ratchet wheel and move it incrementally as described above.

To restrain the pawl actuators when desired, latch means are provided in the form ofa lever 170, 172 pivotally mounted on each bracket at 174, 176 intermediate its ends 178, 180 and 182', 184. Each lever is urged to its latching position in the path of movement of actuator ends 162, 166 by a spring 186.

To release the actuators, lever ends 180, 184 are attracted by coils or attraction magnets 188, 190 connected to the logic center 118. Although attraction magnets are shown, it will be understoodthat solenoids may be used if desired. As used herein, the term solenoids includes attraction magnets.

In order to discontinue the incremental drive action, the logic center sends a signal to each pair of solenoids as its respective pawl rides the high dwell of the eccentric, releasing lever ends 180 and 184 successively. When pawl 126 is fully extended, actuator 152 has turned clockwise sufficiently so that spring 186 can move lever end 178 behind actuator end 162 and prevent its return. The same is true of the other actuator and its latch means.

When the actuators are locked out, springs 142 move the pawls to their outermost positions so that they no longer track the eccentric although it touches them in each revolution. Therefore, they do not enter recesses 44 and do not rotate the ratchet wheel. Heads 134 and 136 rock back and forth in light rubbing contact with actuator ends 160 and 164.

When the time comes to start the incremental drive again, the logic center sends a signal to each solenoid successively to retract its associated latch lever just as the high point of the eccentric extends the respective pawlto its outermost position. Since it is constantly in contact with its respective pawl actuator, the latter now exerts its overriding spring force and the pawl dog smoothly enters its adjacent recess in the ratchet wheel. There is no strain or shock on the ratchet wheel and the first increment is exactly the same as all succeeding incremerits.

It will be apparent to those skilled in the art that various changes may be made in the construction as disclosed without departing from the spirit of the invention, and it is intended that all such changes shall be embraced within the scope of the following claims.

Iclaim:

1. An incremental drive assembly for a record card punching machine, comprising: a support; a central shaft mounted on said support for rotation; a pair of lateral shafts mounted on said support for rotation; said lateral shafts being spaced at opposite sides of said central shaft with their axes parallel to the axis of the central shaft; gear means to drive all of said shafts in predetermined constant relation; an eccentric fixedly mounted on the central shaft for rotation therewith; a pair ofelongate cam follower arms mounted for rocking about the axis of the central shaft independently of its rotation and extending radially outward from the central shaft in opposite directions; an elongate pawl longitudinally slidably mounted on each arm for movement radially inwardly and outwardly with respect to the central shaft and having a head for engagement with a pawl actuator and a foot for engagement with said eccentric; spring means for biasing said pawls toward the pawl actuators; a cam fixedly mounted on each of said lateral shafts for rotation therewith and so located in the plane of said cam follower arms and in contact therewith as to rock each arm in the same angular direction in response to rotation of the cams; the cams being so phased as to rock the arms alternately; spring means engaging each arm to resiliently oppose its rocking movement and constantly urge it toward its cam; a pawl actuator for each pawl in the form of a lever pivotally mounted on the support for swinging in the plane of said pawl and having an end portion conformed to contact the head of the pawl; spring means to bias each actuator toward its respective pawl and override the pawl spring to urge the pawl radially inward toward said eccentric; a ratchet wheel mounted on the axis of rotation of said central shaft for rotation independently of said shaft and having a rim with spaced, outwardly opening recesses; each pawl having a laterally extending dog at its head adapted to engage in an adjacent recess of said ratchet wheel-when the pawl moves inwardly toward said central shaft and to disengage from the recess upon outward movement; said eccentric being so phased with respect to the lobes of said cams that the dog of each pawl head engages the adjacent recess of the ratchet wheel as its respective cam follower arm rocks toward its respective cam in response to the force on of its biasing spring means and moves the ratchet wheel angularly a predetermined incremental distance, and disengages the recess as its respective cam returns it angularly toward its biasing spring means; card feed wheel means incorportated in the punching machine; and said ratchet wheel having a drive shaft coaxial with said central shaft and connected to said wheel means to produce incremental rotation thereof corresponding to the incremental rotation of said ratchet wheel.

2. A drive assembly as claimed in claim 1; and electrical control means for selectively holding each pawl actuator in retracted position and releasing it to force its respective pawl into tracking relation with the eccentric; said control means including means to sense the angular rotational position of the high dwell of the eccentric.

3. A drive assembly as claimed in claim 2, said control means being responsive to signals indicative of the angular rotational position of the high dwell of the eccentric to successively release each pawl actuator when its respective pawl is in contact with the high dwell of the eccentric.

4. A drive assembly as claimed in claim 1; latch means to hold each pawl'actuator in retracted position against the bias of its spring means and allow both pawls to remain at their outermost positions not tracking said eccentric; and electrical means to control the action of said latch means.

5. A drive assembly as claimed in claim 4; said electrical means being adapted to release a latch means when its respective pawl is in contact with the high dwell of said eccentric.

6. A drive assembly as claimed in claim I; a bracket on said support; said pawl actuator being in the form of a lever pivotally mounted intermediate its ends on said bracket and having a first pawl-engaging end and a second latch engaging end; latch means in the form of a lever pivotally mounted on said bracket and having an end adapted to swing to a latching position in the path of the second end of said actuator to prevent the first end from following the pawl toward the axis of the central shaft, and to swing to a release position out of said path to allow free movement of said actuator; and electrical means to control the operation of the latch means.

7. A drive assembly as claimed in claim 6; spring means to urge said latch means to its latching position; and said electrical means including a solenoid actuatable to force said latch means to its release position against the force of its spring means. 

